SARS-CoV-2 B.1.1.7 variant and increased clinical severity – the jury is out
- Frampton D
- Rampling T
- Cross A
- et al.
demonstrated an increase in viral load but not in disease severity or 28-day mortality in hospitalized patients infected with SARS-CoV-2 variant B.1.1.7. In contrast, we found slightly different results when evaluating the risk of morbidity and mortality in a matched case-control study of 60 hospitalized patients — 30 with the B.1.1.7 variant and 30 with the non- variants. B.1.1.7. Cases were matched for admission period and age group. Clinical severity scores, ventilation requirements, treatments received, and 28-day mortality were compared between groups using anonymized and retrospectively collected data and the sum of Wilcoxon ranks and2 or Fisher’s exact tests.
- Challen R
- Brooks-Pollock E
- Read JM
- Dyson L
- Tsaneva-Atanasova K
- Danon L
who studied a younger population than that described here or studied by Frampton and colleagues, with probably less comorbidity, found a 64% increase in mortality at 28 days after community infection with variant B.1.1.7 (control group, 0.26%; Variant group B.1.1.7, 0.41%. Similarly, Davies and colleagues
- Davies NG
- Jarvis CI
- Edmunds WJ
- Jewell NP
- Diaz-Ordaz K
- Keogh HR
concluded that variant B.1.1.7 infections were associated with a 61% higher risk of death (95% CI 42–82) than with pre-existing variants.
BoardDemographics and outcomes of cases of SARS-CoV-2 infection with variant B.1.1.7 compared to non-B.1.1.7 variants
Data are n (%) or median (IQR), unless otherwise noted. FIO2= fraction of inspired oxygen.
We believe that identifying any increased risk of morbidity and mortality in patients infected with variants of concern of SARS-CoV-2 requires sufficiently powerful studies that use a combination of community and hospital PCR swabs, examining the severity of disease using more detailed clinical severity scores (such as the WHO ordinal clinical progression scale used by Frampton and colleagues) with physiological measures, and assessing the impact of viral load, new treatments and vaccinations. For the purposes of future case-control studies, we post-hoc estimate that a sample size of 234 patients in each group is needed to detect an effect size of 11.4% in 28-day mortality for one mortality. baseline in the control group. from 20.7% to 80% power with 5% significance. We believe the jury is still out on whether B.1.1.7 infections are associated with increased mortality, which requires more time and data.
AC reports grants from NIHR, Asthma UK, Boehringer-Ingelheim Charity; Sanofi consulting fees and fees; and GSK support for attendance at meetings. All other authors declare no competing interests.
Genomic characteristics and clinical effect of the emerging SARS-CoV-2 B.1.1.7 line in London, UK: a whole genome and cohort sequencing study in a hospital setting.
Lancet Infect Dis. 2021; ()
Risk of mortality in patients infected with the variant of concern of SARS-CoV-2 202012/1: matched cohort study.
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Increased mortality in cases tested in the community of the SARS-CoV-2 line B.1.1.7.
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© 2021 Elsevier Ltd. All rights reserved.
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